diff --git a/packages/forms/src/directives/abstract_control_directive.ts b/packages/forms/src/directives/abstract_control_directive.ts
index 1a682ec473..d0884eeeb4 100644
--- a/packages/forms/src/directives/abstract_control_directive.ts
+++ b/packages/forms/src/directives/abstract_control_directive.ts
@@ -14,7 +14,7 @@ import {ValidationErrors} from './validators';
  * @description
  * Base class for control directives.
  *
- * This class is only used internally in the `FormsModule`.
+ * This class is only used internally in the `ReactiveFormsModule` and the `FormsModule`.
  *
  */
 export abstract class AbstractControlDirective {
@@ -28,114 +28,94 @@ export abstract class AbstractControlDirective {
 
   /**
    * @description
-   * The value of the control.
-   *
-   * @returns The value of the control if it is present, otherwise null.
+   * Reports the value of the control if it is present, otherwise null.
    */
   get value(): any { return this.control ? this.control.value : null; }
 
   /**
    * @description
-   * Reports that the control is valid, meaning that no errors exist in the input value.
-   *
-   * @returns The control's valid state if the control is present, otherwise null.
+   * Reports whether the control is valid. A control is considered valid if no
+   * validation errors exist with the current value.
+   * If the control is not present, null is returned.
    */
   get valid(): boolean|null { return this.control ? this.control.valid : null; }
 
   /**
    * @description
-   * Reports that the control is invalid, meaning that an error exists in the input value.
-   *
-   * @returns The control's invalid state if the control is present, otherwise null.
+   * Reports whether the control is invalid, meaning that an error exists in the input value.
+   * If the control is not present, null is returned.
    */
   get invalid(): boolean|null { return this.control ? this.control.invalid : null; }
 
   /**
    * @description
-   * Reports that a control is pending, meaning that that async validation is occurring and
-   * errors are not yet available for the input value.
-   *
-   * @returns The control's pending state if the control is present, otherwise null.
+   * Reports whether a control is pending, meaning that that async validation is occurring and
+   * errors are not yet available for the input value. If the control is not present, null is
+   * returned.
    */
   get pending(): boolean|null { return this.control ? this.control.pending : null; }
 
   /**
    * @description
-   * Reports that the control is disabled, meaning that the control is exempt from ancestor
-   * calculations of validity or value.
-   *
-   * @returns The control's disabled state if the control is present, otherwise null.
+   * Reports whether the control is disabled, meaning that the control is disabled
+   * in the UI and is exempt from validation checks and excluded from aggregate
+   * values of ancestor controls. If the control is not present, null is returned.
    */
   get disabled(): boolean|null { return this.control ? this.control.disabled : null; }
 
   /**
    * @description
-   * Reports that the control is enabled, meaning that the control is included in ancestor
-   * calculations of validity or value.
-   *
-   * @returns The control's enabled state if the control is present, otherwise null.
+   * Reports whether the control is enabled, meaning that the control is included in ancestor
+   * calculations of validity or value. If the control is not present, null is returned.
    */
   get enabled(): boolean|null { return this.control ? this.control.enabled : null; }
 
   /**
    * @description
-   * Reports the FormControl validation errors.
-   *
-   * @returns The control's validation errors if the control is present, otherwise null.
+   * Reports the control's validation errors. If the control is not present, null is returned.
    */
   get errors(): ValidationErrors|null { return this.control ? this.control.errors : null; }
 
   /**
    * @description
-   * Reports that the control is pristine, meaning that the control the user has not yet changed
-   * the value in the UI.
-   *
-   * @returns The control's pristine state if the control is present, otherwise null.
+   * Reports whether the control is pristine, meaning that the user has not yet changed
+   * the value in the UI. If the control is not present, null is returned.
    */
   get pristine(): boolean|null { return this.control ? this.control.pristine : null; }
 
   /**
    * @description
-   * Reports that the control is dirty, meaning that the control the user has changed
-   * the value in the UI.
-   *
-   * @returns The control's dirty state if the control is present, otherwise null.
+   * Reports whether the control is dirty, meaning that the user has changed
+   * the value in the UI. If the control is not present, null is returned.
    */
   get dirty(): boolean|null { return this.control ? this.control.dirty : null; }
 
   /**
    * @description
-   * Reports that the control is touched, meaning that the the user has triggered
-   * a `blur` event on it.
-   *
-   * @returns The control's touched state if the control is present, otherwise null.
+   * Reports whether the control is touched, meaning that the user has triggered
+   * a `blur` event on it. If the control is not present, null is returned.
    */
   get touched(): boolean|null { return this.control ? this.control.touched : null; }
 
   /**
    * @description
-   * Reports that a FormControl is touched, meaning that the the user has triggered
-   * a `blur` event on it.
-   *
-   * @returns The control's touched state if the control is present, otherwise null.
+   * Reports the validation status of the control. Possible values include:
+   * 'VALID', 'INVALID', 'DISABLED', and 'PENDING'.
+   * If the control is not present, null is returned.
    */
   get status(): string|null { return this.control ? this.control.status : null; }
 
   /**
    * @description
-   * Reports that a FormControl is untouched, meaning that the the user has not yet triggered
-   * a `blur` event on it.
-   *
-   * @returns The control's untouched state if the control is present, otherwise null.
+   * Reports whether the control is untouched, meaning that the user has not yet triggered
+   * a `blur` event on it. If the control is not present, null is returned.
    */
   get untouched(): boolean|null { return this.control ? this.control.untouched : null; }
 
   /**
    * @description
-   * Reports the observable of status changes for the control.
-   *
-   * @returns An observable that emits every time the validation status of the control
-   * is re-calculated if the control is present, otherwise null.
+   * Returns a multicasting observable that emits a validation status whenever it is
+   * calculated for the control. If the control is not present, null is returned.
    */
   get statusChanges(): Observable<any>|null {
     return this.control ? this.control.statusChanges : null;
@@ -143,10 +123,9 @@ export abstract class AbstractControlDirective {
 
   /**
    * @description
-   * Reports the observable of value changes for the control.
-   *
-   * @returns An observable that emits every time the value of the control
-   * changes in the UI or programmatically if the control is present, otherwise null.
+   * Returns a multicasting observable of value changes for the control that emits every time the
+   * value of the control changes in the UI or programmatically.
+   * If the control is not present, null is returned.
    */
   get valueChanges(): Observable<any>|null {
     return this.control ? this.control.valueChanges : null;
@@ -154,16 +133,14 @@ export abstract class AbstractControlDirective {
 
   /**
    * @description
-   * Reports an array that represents the path from the top-level form to this control.
+   * Returns an array that represents the path from the top-level form to this control.
    * Each index is the string name of the control on that level.
-   *
    */
   get path(): string[]|null { return null; }
 
   /**
    * @description
-   * Resets the control with the provided value if the control is present
-   *
+   * Resets the control with the provided value if the control is present.
    */
   reset(value: any = undefined): void {
     if (this.control) this.control.reset(value);
@@ -173,8 +150,7 @@ export abstract class AbstractControlDirective {
    * @description
    * Reports whether the control with the given path has the error specified.
    * If no path is given, it checks for the error on the present control.
-   *
-   * @returns True if the control is present and has the error specified, otherwise false
+   * If the control is not present, false is returned.
    */
   hasError(errorCode: string, path?: string[]): boolean {
     return this.control ? this.control.hasError(errorCode, path) : false;
@@ -182,10 +158,8 @@ export abstract class AbstractControlDirective {
 
   /**
    * @description
-   * Reports error data for the control with the given path. Otherwise
-   * returns null or undefined.
-   *
-   * @returns The control's error if the control is present, otherwise null
+   * Reports error data for the control with the given path.
+   * If the control is not present, null is returned.
    */
   getError(errorCode: string, path?: string[]): any {
     return this.control ? this.control.getError(errorCode, path) : null;
diff --git a/packages/forms/src/directives/abstract_form_group_directive.ts b/packages/forms/src/directives/abstract_form_group_directive.ts
index 3598a29473..7b423588be 100644
--- a/packages/forms/src/directives/abstract_form_group_directive.ts
+++ b/packages/forms/src/directives/abstract_form_group_directive.ts
@@ -52,7 +52,7 @@ export class AbstractFormGroupDirective extends ControlContainer implements OnIn
 
   /**
    * @description
-   * The callback method triggered on the instance after the inputs are set.
+   * An internal callback method triggered on the instance after the inputs are set.
    * Registers the group with its parent group.
    */
   ngOnInit(): void {
@@ -62,7 +62,7 @@ export class AbstractFormGroupDirective extends ControlContainer implements OnIn
 
   /**
    * @description
-   * The callback method trigger before the instance is destroyed.
+   * An internal callback method triggered before the instance is destroyed.
    * Removes the group from its parent group.
    */
   ngOnDestroy(): void {
@@ -73,33 +73,31 @@ export class AbstractFormGroupDirective extends ControlContainer implements OnIn
 
   /**
    * @description
-   * Reports the `FormGroup` bound to this directive from its parent
+   * The `FormGroup` bound to this directive.
    */
   get control(): FormGroup { return this.formDirective !.getFormGroup(this); }
 
   /**
    * @description
-   * Reports the path to this group
+   * The path to this group from the top-level directive.
    */
   get path(): string[] { return controlPath(this.name, this._parent); }
 
   /**
    * @description
-   * Reports the parent form for this group
-   *
-   * @returns The parent form if present, otherwise null.
+   * The top-level directive for this group if present, otherwise null.
    */
   get formDirective(): Form|null { return this._parent ? this._parent.formDirective : null; }
 
   /**
    * @description
-   * Reports the synchronous validators registered with this group
+   * The synchronous validators registered with this group.
    */
   get validator(): ValidatorFn|null { return composeValidators(this._validators); }
 
   /**
    * @description
-   * Reports the async validators registered with this group
+   * The async validators registered with this group.
    */
   get asyncValidator(): AsyncValidatorFn|null {
     return composeAsyncValidators(this._asyncValidators);
diff --git a/packages/forms/src/directives/control_container.ts b/packages/forms/src/directives/control_container.ts
index a6529386a9..747a6b11ca 100644
--- a/packages/forms/src/directives/control_container.ts
+++ b/packages/forms/src/directives/control_container.ts
@@ -25,13 +25,13 @@ export abstract class ControlContainer extends AbstractControlDirective {
 
   /**
    * @description
-   * Reports the parent form for the control
+   * The top-level form directive for the control.
    */
   get formDirective(): Form|null { return null; }
 
   /**
    * @description
-   * Reports the path to this group
+   * The path to this group.
    */
   get path(): string[]|null { return null; }
 }
diff --git a/packages/forms/src/directives/control_value_accessor.ts b/packages/forms/src/directives/control_value_accessor.ts
index 30f3d90147..aa90ecb045 100644
--- a/packages/forms/src/directives/control_value_accessor.ts
+++ b/packages/forms/src/directives/control_value_accessor.ts
@@ -55,7 +55,7 @@ export interface ControlValueAccessor {
    *
    * The following example stores the provided function as an internal method.
    *
-   * ```typescript
+   * ```ts
    * registerOnChange(fn: (_: any) => void): void {
    *   this._onChange = fn;
    * }
@@ -64,7 +64,7 @@ export interface ControlValueAccessor {
    * When the value changes in the UI, call the registered
    * function to allow the forms API to update itself:
    *
-   * ```typescript
+   * ```ts
    * host: {
    *    (change): '_onChange($event.target.value)'
    * }
@@ -76,10 +76,8 @@ export interface ControlValueAccessor {
 
   /**
    * @description
-   * Registers a callback function that is called when the control receives a blur event.
-   *
-   * This is called by the forms API on initialization so it can update the form model
-   * on blur.
+   * Registers a callback function is called by the forms API on initialization
+   * to update the form model on blur.
    *
    * When implementing `registerOnTouched` in your own value accessor, save the given
    * function so your class calls it when the control should be considered
@@ -87,7 +85,7 @@ export interface ControlValueAccessor {
    *
    * ### Store the callback function
    *
-   * The folliwing example stores the provided function as an internal method.
+   * The following example stores the provided function as an internal method.
    *
    * ```ts
    * registerOnTouched(fn: any): void {
@@ -95,7 +93,7 @@ export interface ControlValueAccessor {
    * }
    * ```
    *
-   * On blur (or equivalent), your class calls the registered function to allow
+   * On blur (or equivalent), your class should call the registered function to allow
    * the forms API to update itself:
    *
    * ```ts
@@ -110,8 +108,8 @@ export interface ControlValueAccessor {
 
   /**
    * @description
-   * Registers a callback function that is called when the control status is disabled or
-   * re-enabled. Depending on the status, it enables or disables the
+   * Function that is called by the forms API when the control status changes to
+   * or from 'DISABLED'. Depending on the status, it enables or disables the
    * appropriate DOM element.
    *
    * The following is an example of writing the disabled property to a native DOM element:
diff --git a/packages/forms/src/directives/form_interface.ts b/packages/forms/src/directives/form_interface.ts
index 1a52b623cc..f58e60ddfd 100644
--- a/packages/forms/src/directives/form_interface.ts
+++ b/packages/forms/src/directives/form_interface.ts
@@ -17,14 +17,14 @@ import {NgControl} from './ng_control';
  * @description
  * An interface implemented by `FormGroupDirective` and `NgForm` directives.
  *
- * Only used by the `FormsModule`.
+ * Only used by the `ReactiveFormsModule` and `FormsModule`.
  */
 export interface Form {
   /**
    * @description
    * Add a control to this form.
    *
-   * @param dir The control to add to the form
+   * @param dir The control directive to add to the form.
    */
   addControl(dir: NgControl): void;
 
@@ -32,15 +32,15 @@ export interface Form {
    * @description
    * Remove a control from this form.
    *
-   * @param dir: The control to remove from the form
+   * @param dir: The control directive to remove from the form.
    */
   removeControl(dir: NgControl): void;
 
   /**
    * @description
-   * Reports the `FormControl` associated with the provided `NgControl`.
+   * The control directive from which to get the `FormControl`.
    *
-   * @param dir: The form control instance
+   * @param dir: The control directive.
    */
   getControl(dir: NgControl): FormControl;
 
@@ -48,7 +48,7 @@ export interface Form {
    * @description
    * Add a group of controls to this form.
    *
-   * @param dir: The control group to remove
+   * @param dir: The control group directive to add.
    */
   addFormGroup(dir: AbstractFormGroupDirective): void;
 
@@ -56,15 +56,15 @@ export interface Form {
    * @description
    * Remove a group of controls to this form.
    *
-   * @param dir: The control group to remove
+   * @param dir: The control group directive to remove.
    */
   removeFormGroup(dir: AbstractFormGroupDirective): void;
 
   /**
    * @description
-   * Reports the form group for the provided control
+   * The `FormGroup` associated with a particular `AbstractFormGroupDirective`.
    *
-   * @param dir: The form group to query
+   * @param dir: The form group directive from which to get the `FormGroup`.
    */
   getFormGroup(dir: AbstractFormGroupDirective): FormGroup;
 
@@ -72,8 +72,8 @@ export interface Form {
    * @description
    * Update the model for a particular control with a new value.
    *
-   * @param dir: The control to update
-   * @param value: The new value for the control
+   * @param dir: The control directive to update.
+   * @param value: The new value for the control.
    */
   updateModel(dir: NgControl, value: any): void;
 }
diff --git a/packages/forms/src/directives/ng_control.ts b/packages/forms/src/directives/ng_control.ts
index 4becf75adb..2affcbe0fa 100644
--- a/packages/forms/src/directives/ng_control.ts
+++ b/packages/forms/src/directives/ng_control.ts
@@ -18,13 +18,14 @@ function unimplemented(): any {
 
 /**
  * @description
- * A base class that all control directives extend. It binds a `FormControl` object to a
- * DOM element and is only used internally by Angular forms.
+ * A base class that all control `FormControl`-based directives extend. It binds a `FormControl`
+ * object to a DOM element.
  */
 export abstract class NgControl extends AbstractControlDirective {
   /**
    * @description
-   * The parent form for the control
+   * The parent form for the control.
+   *
    * @internal
    */
   _parent: ControlContainer|null = null;
diff --git a/packages/forms/src/directives/validators.ts b/packages/forms/src/directives/validators.ts
index 5b615d0f1b..c9727435a5 100644
--- a/packages/forms/src/directives/validators.ts
+++ b/packages/forms/src/directives/validators.ts
@@ -36,11 +36,11 @@ export type ValidationErrors = {
  *
  * ```typescript
  * @Directive({
- *   selector: '[custom-validator]',
+ *   selector: '[customValidator]',
  *   providers: [{provide: NG_VALIDATORS, useExisting: CustomValidatorDirective, multi: true}]
  * })
  * class CustomValidatorDirective implements Validator {
- *   validate(c: AbstractControl): {[key: string]: any} {
+ *   validate(c: AbstractControl): ValidationErrors|null {
  *     return {'custom': true};
  *   }
  * }
@@ -49,7 +49,7 @@ export type ValidationErrors = {
 export interface Validator {
   /**
    * @description
-   * Method that performs synchronous verification against the provided control.
+   * Method that performs synchronous validation against the provided control.
    *
    * @param c The control to validate against.
    *
@@ -82,12 +82,12 @@ export interface Validator {
  * import { of as observableOf } from 'rxjs';
  *
  * @Directive({
- *   selector: '[custom-async-validator]',
+ *   selector: '[customAsyncValidator]',
  *   providers: [{provide: NG_ASYNC_VALIDATORS, useExisting: CustomAsyncValidatorDirective, multi:
  * true}]
  * })
  * class CustomAsyncValidatorDirective implements AsyncValidator {
- *   validate(c: AbstractControl): Observable<{[key: string]: any}> {
+ *   validate(c: AbstractControl): Observable<ValidationErrors|null> {
  *     return observableOf({'custom': true});
  *   }
  * }
@@ -98,7 +98,7 @@ export interface Validator {
 export interface AsyncValidator extends Validator {
   /**
    * @description
-   * Method that performs async verification against the provided control.
+   * Method that performs async validation against the provided control.
    *
    * @param c The control to validate against.
    *